助熔剂工艺制备硼酸镁（Mg2B2O5）晶须的扩试研究

对以六水氯化镁、硼酸、氢氧化钠为原料,氯化钠为助熔剂制备硼酸镁(Mg2B2O5)晶须的工艺进行了百吨级扩试。研究了温度、硼镁比例、助熔剂含量等对晶须组成和形貌的影响。应用容量分析、X射线衍射仪(XRD)、扫描电镜(SEM)以及颗粒统计系统对制备的晶须进行了检测和表征。通过工艺优化得到了硼酸镁晶须的最佳合成条件:温度为880℃,硼镁的最佳摩尔比为1.4、助熔剂与镁的最佳摩尔比为3.0。XRD分析表明制备的产品为单一相三斜结构硼酸镁(Mg2B2O5);SEM电镜分析表明制备的晶须形貌规整,无团聚;颗粒统计系统分析表明直径在1～5μm之间的晶须占统计总数的96.36%,长度在40～60μm之间的晶须占统计总数的69.25%。该扩试的完成为推动硼酸镁晶须的应用起到了积极的作用。

Scale up experiment on synthesis of magnesium borate(Mg2B2O5)whisker by flux method

100t/a scale up experiment was performed to synthesize magnesium borate(Mg2B2O5) whisker by flux method using magnesium chloride hexahydrate,boric acid,sodium hydroxide as raw materials and sodium chloride as flux agent.Effects of temperature,mol ratio of B/Mg and flux agent on composition and morphology of magnesium borate whisker were studied in detail.The as-prepared sample was characterized and analysed by X-Ray Diffraction(XRD),Scanning Electron Microscopy(SEM),particles statistic system and titration method.Results showed that the optimal synthesis temperature,ratio of B and Mg,flux agent and Mg were 850℃,1.4 and 3.0,respectively.XRD confirmed that the as-prepared sample in optimal conditions was triclinic structure and SEM showed that whiskers were uniform distribution particles without aggregation.Particle statistical system confirmed that diameter of the whiskers between 1μm and 5μm accounted for 96.36% and length between 40μm and 60μm accounted for 69.25% of the total.The successful scale up experiment played a positive role in promoting the application of magnesium borate whisker.